Is it feasible in a patch to allow for some countries in an alliance to be human and some AI? I would love for example to play a game with me as UK my Wife as France and my brother as Russia and let all the other entente nations be AI? I know one cannot do that now, but is it even possible that a patch could allow something like this.

AFAIK the Slitherine server only allows 2 players atm. Technically it should be possible to coop against an AI opponent, but it would be quite a lot of work to implement. Will keep it in mind for the future. I'm a big fan of teamplay myself.